Railroad trailer chassis

ABSTRACT

A railroad trailer chassis comprising two or more road axles, two or more rail axles operable to be moved between first and second positions, and a work unit. The railroad trailer chassis is operable to be driven or towed in a road mode when the two or rail axles are in their respective first positions. The railroad trailer chassis is operable to be driven or towed in a rail mode when the two or more rail axles are in their respective second positions. The work unit is operable to perform one or more railroad maintenance or operation functions when driven in the rail mode.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of application Ser. No.14/615,535 filed on Feb. 6, 2015, which claims priority to U.S.Provisional Patent Application No. 61/936,377 entitled “RAILROAD TRAILERCHASSIS” filed on Feb. 6, 2014, each of which is incorporated herein byreference in their entirety.

TECHNICAL FIELD

The present disclosure generally relates to a rail trailer forperforming maintenance or inspection operations, and more particularlyto a railroad trailer chassis that may be towed on a road, driven on aroad, towed on a rail, or driven on a rail to perform various functionson railroad tracks.

BACKGROUND

Railroads are typically constructed to include a pair of elongated,substantially parallel rails, which are coupled to a plurality oflaterally extending ties. The ties are disposed on a ballast bed of hardparticulate material such as gravel. Over time, normal wear and tear onthe railroad may cause the rails to deviate from a desired profile.

Railroad maintenance equipment is often large, heavy equipment. However,in order to justify the size and the cost of large rail equipment, arailroad operator would need to maintain a large amount of railwaytrack. In order for the rail equipment to be used on a particularportion of track, the rail equipment would need to be driven on the railto the desired location or shipped to the desired location on aspecialty shipping trailer. However, rail equipment is often slow movingand special shipping permits may be needed to ship a full-sized railequipment. Even after shipping rail equipment in a specialty trailer, acrane may be needed to lift the rail equipment from the trailer to setthe rail equipment onto the tracks.

Therefore, smaller, more maneuverable railroad equipment that may beused on both the rail and the road is desired.

BRIEF SUMMARY

The present disclosure is related to a railroad trailer chassis. Therailroad trailer chassis described herein may be a trailer capable ofbeing towed on roads, driven on roads, towed on rails, or driven onrails. In one embodiment, the railroad trailer chassis may have a caband a work unit capable of being driven under its own power or towedfrom a foldable towing hitch.

A railroad trailer chassis comprising two or more road axles, two ormore rail axles operable to be moved between first and second positions,and a work unit. The railroad trailer chassis is operable to be drivenor towed in a road mode when the two or rail axles are in theirrespective first positions. The railroad trailer chassis is operable tobe driven or towed in a rail mode when the two or more rail axles are intheir respective second positions. The work unit is operable to performone or more railroad maintenance or operation functions when driven inthe rail mode.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example in the accompanyingfigures, in which like reference numbers indicate similar parts, and inwhich:

FIG. 1 illustrates a perspective view of a railroad trailer chassis, inaccordance with one embodiment of the present disclosure;

FIG. 2 illustrates a side view of the railroad trailer chassis of FIG. 1in road mode, in accordance with one embodiment of the presentdisclosure;

FIG. 3 illustrates an end view of the railroad trailer chassis of FIG. 2in road mode, in accordance with one embodiment of the presentdisclosure;

FIG. 4 illustrates a side view of the railroad trailer chassis of FIG. 1in rail mode, in accordance with one embodiment of the presentdisclosure;

FIG. 5 illustrates an end view of the railroad trailer chassis of FIG. 4in rail mode, in accordance with one embodiment of the presentdisclosure;

FIG. 6 illustrates a perspective view of a combination of the railroadtrailer chassis of FIG. 1 and a truck, in accordance with one embodimentof the present disclosure;

FIG. 7 illustrates a side view of the combination of the railroadtrailer chassis and the truck of FIG. 6 in road tow mode, in accordancewith one embodiment of the present disclosure;

FIG. 8 illustrates a perspective view of a combination of two railroadtrailer chassis of FIG. 1 in rail tow mode, in accordance with oneembodiment of the present disclosure;

FIG. 9 illustrates a perspective view of an undercarriage unit of therailroad trailer chassis of FIG. 1 in road mode, in accordance with oneembodiment of the present disclosure;

FIG. 10 illustrates a perspective view of the undercarriage unit of FIG.9 in rail mode, in accordance with one embodiment of the presentdisclosure;

FIG. 11 illustrates a side view of a railroad trailer chassis with afriction drive system in road mode, in accordance with one embodiment ofthe present disclosure;

FIG. 12 illustrates a side view of the railroad trailer chassis of FIG.11 in rail mode, in accordance with one embodiment of the presentdisclosure; and

FIG. 13 illustrates a side view of a combination of the railroad trailerchassis of FIG. 11 and a truck in road tow mode, in accordance with oneembodiment of the present disclosure.

DETAILED DESCRIPTION

Various embodiments of a railroad trailer chassis and methods of usingsuch a railroad trailer chassis according to the present disclosure aredescribed. It is to be understood, however, that the followingexplanation is merely exemplary in describing the devices and methods ofthe present disclosure. Accordingly, several modifications, changes, andsubstitutions are contemplated.

In the embodiments described herein, the railroad trailer chassis is adrivable trailer. The railroad trailer chassis may be configured toperform any railroad maintenance or inspection operations. The railroadtrailer chassis is capable of being towed on a road at highway speeds,driven on the road under its own power at reduced speeds, towed on arail at railroad speeds, or driven on the rail at medium-slow speeds.

In the embodiments described herein, the railroad trailer chassis isdepicted and described as a railroad grinding vehicle, however it shouldbe understood that any railroad maintenance and/or inspection operationsequipment could incorporate the disclosed railroad trailer chassis andthe disclosed work unit is a generic work unit that can be configuredfor a variety of purposes. For example, the railroad trailer chassis maybe used for utility vehicles, inspection vehicles, or other trackmaintenance equipment.

FIG. 1 illustrates a perspective view of a railroad trailer chassis 100,in accordance with one embodiment of the present disclosure. In anembodiment, the railroad trailer chassis 100 may be configured as arailroad grinding vehicle 102 comprising a work unit 104, two or moreroad axles 106, two or more rail axles 108, an engine compartment 110,and a foldable towing hitch 112, among other components. However, it isunderstood that in other embodiments, the railroad trailer chassis 100may be configured with any number of road and/or rail axles, as requiredby the specific application desired for the railroad trailer chassis100. Each road axle 106 may be configured with two road wheels 114 andtires 116 and each rail axle 108 may be configured with two rail wheels118.

In an embodiment, the work unit 104 may be interchangeable betweenvarious work units, including work units configured for utilityvehicles, inspection vehicles, or other track maintenance equipment. Inaddition, more than one work unit 104 may be used on a single railroadtrailer chassis 100 and the work unit 104 may be removably attached tothe railroad trailer chassis 100 so that more than one work unit 104 maybe used with a single railroad trailer chassis 100.

In an embodiment, the work unit 104 may be permanently attached to therailroad trailer chassis 100 and may be modular components. Further, inan embodiment, the work unit 104 and the railroad trailer chassis 100may be manufactured as an integral, single component. By manufacturingthe work unit 104 and the railroad trailer chassis 100 as an integralcomponent, a single component may be structurally stronger and lighterweight when compared with a configuration comprising modular work unit104 and railroad trailer chassis 100 components.

The railroad trailer chassis 100 may be configured with any variety ofpower plants and propulsion systems that are operable to propel therailroad trailer chassis in either road driving mode or rail drivingmode. In one embodiment, the railroad trailer grinder may be powered bya Caterpillar Inc. C7.1 Tier 4 final power unit located within theengine compartment 110 and may be propelled by a parallel propel system.

In addition, the railroad trailer chassis 100 may further comprisecomponents from traditional railroad maintenance or inspection vehicles.These components may include a stone grinding carriage, grinding pumps,an integral dust collection system, a low pressure water system, a trackgeometry inspection unit, a liquid based fire suppression system, or anyother track maintenance or inspection equipment. In an embodiment, thestone grinding carriage may comprise multiple stone grinders usingvarious grinding stone heads. Water and fuel capacities may be tailoredto an individual operator's needs. In an embodiment, the railroadtrailer chassis may be configured to store approximately 2000 liters ofwater and fuel, combined. The railroad trailer chassis may furthercomprise remote control operation systems, a water cannon, a highpressure water system, a PTZ camera system, rail profile measurementcapabilities, a corrugation system, and the ability to link two or morechassis together to create a multiple car consist.

In an embodiment, both the road axles 106 and the rail axles 108 may behydraulically powered and be operable to be moved between respectivefirst and second positions. The road axles 106 may be powered, liftable,and steerable, and may be controlled via a control means in a cabin ofthe railroad trailer chassis 100. The rail axles 108 may also be poweredand may be strong enough to support the weight of the entire railroadtrailer chassis 100 when the rail axles 108 are extended downwardly,raising the road axles 106 and the railroad trailer chassis 100 abovethe rail.

In some embodiments, the railroad trailer chassis 100 may be controlledby a remote control external of the railroad trailer chassis 100 in adrone configuration, i.e., without a human inside the railroad trailerchassis 100.

In an embodiment, only the rail axles 108 may be hydraulically poweredand operable to be moved between respective first and second positions,while the road axles 106 may be fixed in a first position on therailroad trailer chassis 100. The rail axles 108 may be strong enough tosupport the weight of the entire railroad trailer chassis 100 when therail axles 108 are extended downwardly, raising the railroad trailerchassis 100 above the rail.

When an operator desires to move the railroad trailer chassis from theroad to the rail, the railroad trailer chassis 100 may be operable tomove between road and rail under its own power and without the use of acrane or other assistance. Alternatively, a crane or other piece ofequipment may be used to move the railroad trailer chassis between theroad and the rail.

Advantageously, the disclosed railroad trailer chassis 100 is a drivabletrailer. Therefore, the trailer may fall under the less stringentFederal Highway Regulations, thus allowing it to be more easily approvedfor on-road use. In addition, as a drivable trailer, the work equipmenton the railroad trailer chassis would not need to be configured to anover-the-road truck chassis native to a specific country. There would beno need to redesign the machine for different trucks or changing modelyear trucks. There is also the potential to use the mobile trailerplatform as the basis for machines such as rail grinders, smallinspection vehicles, utility vehicles, other track maintenanceequipment, and the like.

FIG. 2 illustrates a side view and FIG. 3 illustrates an end view of therailroad trailer chassis 100 of FIG. 1 in road mode, in accordance withone embodiment of the present disclosure. As depicted in FIGS. 2 and 3,the road axles 106 may be in a first position wherein the road tires 116interact with the surface of a road 120 and the rail axles 108 may be ina first position wherein the rail wheels 118 are raised above thesurface of the road 120. In road mode, the work unit 104 may be raisedabove the surface of the road 120.

In road mode, the railroad trailer chassis 100 may be driven down theroad 120 under its own power or may be towed down the road 120 by a towvehicle such as a truck (not shown).

FIG. 4 illustrates a side view and FIG. 5 illustrates an end view of therailroad trailer chassis 100 of FIG. 1 in rail mode, in accordance withone embodiment of the present disclosure. In an embodiment, the roadaxles 106 may be in a second position wherein the road tires 118 areraised above the surface of a rail 122 and the rail axles 108 may be ina second position wherein the rail wheels 118 interact with the surfaceof the rail 122. In an alternative embodiment, the road axles 106 mayremain in a first position and the rail axles 108 may be in a secondposition, lifting the railroad trailer chassis 100 such that the railwheels 118 interact with the surface of the rail 122 and the road tires116 are raised above the surface of the rail 122. In rail mode, the workunit 104 may be proximate to the surface of the rail 122.

In rail mode, the railroad trailer chassis 100 may be driven down therail 122 under its own power or may be towed down the rail 122 by a towvehicle such as a second railroad trailer chassis (not shown).

FIG. 6 illustrates a perspective view and FIG. 7 illustrates a side viewof a combination 200 of the railroad trailer chassis 100 of FIG. 1 and atruck 202 in road tow mode, in accordance with one embodiment of thepresent disclosure. In road tow mode, both the road axles 106 and therail axles 108 of the railroad trailer chassis 100 are in theirrespective first positions. When an operator desires to tow the railroadtrailer chassis 100 along a road 120 in row tow mode, the foldabletrailer towing hitch 112 may be folded downwardly in to a substantiallyhorizontal orientation and connected to the truck 202 or other towvehicle at a trailer hitch 204. When the railroad trailer chassis 100 isoperating under its own power on the road 120, the foldable trailertowing hitch 112 may be locked into a substantially verticalorientation, thereby moving the foldable trailer towing hitch 112 out ofthe way.

FIG. 8 illustrates a perspective view of a combination 300 of tworailroad trailer chassis 100 a, 100 b of FIG. 1 in rail tow mode, inaccordance with one embodiment of the present disclosure. In rail towmode, the road axles 106 and the rail axles 108 of both the firstrailroad trailer chassis 100 a and the second railroad trailer chassis100 b are in their respective second positions. When an operator desiresto tow the first railroad trailer chassis 100 a with the second railroadtrailer chassis 100 b down the rail 122 in rail tow mode, a railconnector 302 may be used to connect the first railroad trailer chassis100 a to the second railroad trailer chassis 100 b. In rail tow mode,the foldable trailer towing hitch 112 of each railroad trailer chassis100 a, 100 b may be locked into a substantially vertical orientation,thereby moving each foldable trailer towing hitch 112 out of the way.

FIG. 9 illustrates a perspective view of an undercarriage unit 400 ofthe railroad trailer chassis of FIG. 1 in road mode, in accordance withone embodiment of the present disclosure. FIG. 10 illustrates aperspective view of the undercarriage unit 400 of FIG. 9 in rail mode,in accordance with one embodiment of the present disclosure.

The undercarriage unit 400 may comprise the work unit 104, which in anembodiment may be a grinder work unit. The rail axles 108 may beconnected to the work unit 104 at one or more lifting devices 402 thatare operable to move the rail axles 108 between their respective firstand second positions. In an embodiment, the one or more lifting devices402 may be hydraulic cylinders. Each lifting device 402 may have amounting bracket 408 affixed to an upper portion of each lifting device402 and may be connected to an underside of a frame of the railroadtrailer chassis (not shown).

In road mode, as shown in FIG. 9, the one or more lifting devices 402may be retracted such that the rail axles 108 are in their firstpositions, as discussed above, wherein the rail axels 108 and the workunit 104 are proximate to the underside of the frame of the railroadtrailer chassis (not shown) and raised above the surface of the rail.

In rail mode, as shown in FIG. 10, the one or more lifting devices 402may be extended such that the rail axles 108 are in their secondpositions, wherein the rail axles 108 and the work unit 104 are extendedaway from the underside of the frame of the railroad trailer chassis(not shown) and the rail wheels 118 are in contact with the surface ofthe rail. In rail mode, the rail axles 108 may be driven by a pluralityof gears and/or chains 404 and a transmission 406 coupled with one ormore rail propel motors (not shown) of the railroad trailer chassis thatare operable to propel the railroad trailer chassis down the rail.

FIG. 11 illustrates a side view of a railroad trailer chassis 500 with afriction drive system in road mode, in accordance with one embodiment ofthe present disclosure. In an embodiment, the railroad trailer chassis500 may be configured as a railroad grinding vehicle 502 comprising awork unit 504, two road axles 506, three rail axles 508, an enginecompartment 510, a foldable towing hitch 512, and friction drive systems514, among other components. However, it is understood that in otherembodiments, the railroad trailer chassis 500 may be configured with anynumber of road and/or rail axles, as required by the specificapplication desired for the railroad trailer chassis 500. Each road axle506 may be configured with two road wheels 516 and tires 518 and eachrail axle 508 may be configured with two rail wheels 520.

In an embodiment, the work unit 504 may be interchangeable betweenvarious different work units, including work units configured forutility vehicles, inspection vehicles, or other track maintenanceequipment. In addition, more than one work unit 504 can be used on asingle railroad trailer chassis 500 and the work unit 504 may beremovably attached to the railroad trailer chassis 500 so that more thanone work unit 504 may be used with a single railroad trailer chassis500.

In an embodiment, the work unit 504 may be permanently affixed to therailroad trailer chassis 500 and may be separate components. Further, inan embodiment, the work unit 504 and the railroad trailer chassis 500may be manufactured as a single component. By manufacturing the workunit 504 and the railroad trailer chassis 500 as a single component, thesingle component may be structurally stronger and lighter weight whencompared with a configuration comprising separate work unit 504 andrailroad trailer chassis 500 components.

The railroad trailer chassis 500 may be configured with any variety ofpower plants and propulsion systems that are operable to propel therailroad trailer chassis in either road driving mode or rail drivingmode. In one embodiment, the railroad trailer grinder may be powered bya Caterpillar Inc. C7.1 Tier 4 final power unit located within theengine compartment 510 and may be propelled by a parallel propel system.

In addition, the railroad trailer chassis 500 may further comprisecomponents from traditional railroad maintenance or inspection vehicles.These components may include a stone grinding carriage, grinding pumps,an integral dust collection system, a low pressure water system, a trackgeometry inspection unit, a liquid based fire suppression system, or anyother track maintenance or inspection equipment. In an embodiment, thestone grinding carriage may comprise multiple stone grinders usingvarious grinding stone heads. Water and fuel capacities may be tailoredto an individual operator's needs. In an embodiment, the railroadtrailer chassis may be configured to store approximately 2000 liters ofwater and fuel, combined. The railroad trailer chassis may furthercomprise remote control operation systems, a water cannon, a highpressure water system, a PTZ camera system, rail profile measurementcapabilities, a corrugation system, and the ability to link two or morechassis together to create a multiple car consist.

In an embodiment, the road axles 506 may be powered, liftable, andsteerable, and may be controlled via a control means in a cabin of therailroad trailer chassis 100 or a remote control. The rail axles 508 maybe operable to pivot from first positions to second positions withfriction drive systems 514. The rail axles 508 and the friction drivesystems 514 may be strong enough to support the weight of the entirerailroad trailer chassis 500 when the rail axles 508 are pivoteddownwardly, raising the railroad trailer chassis 500 off of the rail.

In road mode, the rail axles 508 are pivoted upwardly by the frictiondrive systems 514 such that the rail wheels 520 are not in contact withthe road tires 518. As depicted in FIG. 11, the road axles 506 may be ina first position wherein the road tires 518 interact with the surface ofa road 522 and the rail axles 508 may be in a first position wherein therail wheels 520 are raised above the surface of the road 522. In roadmode, the railroad trailer chassis 500 may be driven down the road 522under its own power or may be towed down 522 the road by a tow vehiclesuch as a truck (not shown).

When both the road axles and the rail axles are in the their respectivefirst positions, the railroad trailer chassis 500 is operable to betowed in road towing mode or driven down the road in road driving mode.

FIG. 12 illustrates a side view of the railroad trailer chassis 500 ofFIG. 11 in rail mode, in accordance with one embodiment of the presentdisclosure. In road mode, the rail axles 508 are pivoted downwardly bythe friction drive systems 514 such that the rail wheels 520 are incontact with the road tires 518. As depicted in FIG. 12, the rail axles508 may be in a second position wherein the rail wheels 520 are loweredto the surface of a rail 524. In rail mode, the railroad trailer chassis500 may be driven down the rail 524 under its own power or may be toweddown the rail 524 by a tow vehicle such as a second railroad trailerchassis (not shown).

In rail mode, the road axles 506 drive the railroad trailer chassis 500down the rail 524 by rotating the road axles 508 and the road tires 518that are in friction contact with the rail wheels 520. The rear roadaxle 506 (road axle 506 closer to engine compartment 510) may utilize adual friction drive 514 with one friction drive 514 on each side of theroad axle 506 so that the dual friction drive 514 cradles the rear roadtires 518. In an embodiment, the rear road axle 506 may be a pivotingfifth wheel setup, allowing the rear road axle 506 and the dual frictiondrive 514 to create a railroad bogie, which provides more stability andallows the railroad trailer chassis 500 to travel on tighter curves ofthe rail 524 as a result of the increased distance between the railaxles 508.

The front road axle 506 (road axle 506 closer to engine compartment 510)may utilize a single friction drive 514 with one friction drive 514forward of the front road axle 506, which does not pivot

FIG. 13 illustrates a side view of a combination 600 the railroadtrailer chassis 500 of FIG. 11 and a truck 602 in road tow mode, inaccordance with one embodiment of the present disclosure. In road towmode, both the road axles 506 and the rail axles 508 of the railroadtrailer chassis 500 are in their respective first positions. When anoperator desires to tow the railroad trailer chassis 500 along a road522 in row tow mode, the foldable trailer towing hitch 512 may be foldeddownwardly in to a substantially horizontal orientation and connected tothe truck 602 or other towing vehicle at a trailer hitch 604. When therailroad trailer chassis 500 is operating under its own power on theroad (not shown), the foldable trailer towing hitch 512 may be lockedinto a substantially vertical orientation, thereby moving the foldabletrailer towing hitch 512 out of the way.

Advantageously, utilizing a friction drive system 514 increases thewheelbase of the railroad trailer chassis 500, making the railroadtrailer chassis 500 safer and more stable, and the propel motors forpropelling the road axles 506 may be used for both road and rail travel.

While various embodiments in accordance with the disclosed principleshave been described above, it should be understood that they have beenpresented by way of example only, and are not limiting. Thus, thebreadth and scope of the invention(s) should not be limited by any ofthe above-described exemplary embodiments, but should be defined only inaccordance with the claims and their equivalents issuing from thisdisclosure. Furthermore, the above advantages and features are providedin described embodiments, but shall not limit the application of suchissued claims to processes and structures accomplishing any or all ofthe above advantages.

It will be understood that the principal features of this disclosure canbe employed in various embodiments without departing from the scope ofthe disclosure. Those skilled in the art will recognize, or be able toascertain using no more than routine experimentation, numerousequivalents to the specific procedures described herein. Suchequivalents are considered to be within the scope of this disclosure andare covered by the claims.

Additionally, the section headings herein are provided for consistencywith the suggestions under 37 CFR 1.77 or otherwise to provideorganizational cues. These headings shall not limit or characterize theinvention(s) set out in any claims that may issue from this disclosure.Specifically and by way of example, although the headings refer to a“Field of Invention,” such claims should not be limited by the languageunder this heading to describe the so-called technical field. Further, adescription of technology in the “Background of the Invention” sectionis not to be construed as an admission that technology is prior art toany invention(s) in this disclosure. Neither is the “Summary” to beconsidered a characterization of the invention(s) set forth in issuedclaims. Furthermore, any reference in this disclosure to “invention” inthe singular should not be used to argue that there is only a singlepoint of novelty in this disclosure. Multiple inventions may be setforth according to the limitations of the multiple claims issuing fromthis disclosure, and such claims accordingly define the invention(s),and their equivalents, that are protected thereby. In all instances, thescope of such claims shall be considered on their own merits in light ofthis disclosure, but should not be constrained by the headings set forthherein.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps.

As used herein, words of approximation such as, without limitation,“about”, “substantial” or “substantially” refers to a condition thatwhen so modified is understood to not necessarily be absolute or perfectbut would be considered close enough to those of ordinary skill in theart to warrant designating the condition as being present. The extent towhich the description may vary will depend on how great a change can beinstituted and still have one of ordinary skilled in the art recognizethe modified feature as still having the required characteristics andcapabilities of the unmodified feature. In general, but subject to thepreceding discussion, a numerical value herein that is modified by aword of approximation such as “about” may vary from the stated value byat least ±1, 2, 3, 4, 5, 6, 7, 10, 12 or 15%.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof is intended to include atleast one of: A, B, C, AB, AC, BC, or ABC, and if order is important ina particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, AB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of thisdisclosure have been described in terms of preferred embodiments, itwill be apparent to those of skill in the art that variations may beapplied to the compositions and/or methods and in the steps or in thesequence of steps of the method described herein without departing fromthe concept, spirit and scope of the disclosure. All such similarsubstitutes and modifications apparent to those skilled in the art aredeemed to be within the spirit, scope and concept of the disclosure asdefined by the appended claims.

What is claimed is:
 1. A railroad trailer chassis, comprising: two ormore road axles; two or more rail axles configured to be moved betweenfirst and second positions; a work unit configured to perform one ormore railroad maintenance or operation functions when the railroadtrailer chassis is driven in a rail mode; and a foldable trailer towinghitch configured to, in a horizontal orientation, couple the railroadtrailer chassis to a tow vehicle, wherein the railroad trailer chassisis configured to be towed in a road mode when the two or more rail axlesare respectively in the first positions, and the railroad trailerchassis is configured to be driven in the rail mode when the two or morerail axles are respectively in the second positions.
 2. The railroadtrailer chassis of claim 1, wherein the two or more rail axles arehydraulically powered.
 3. The railroad trailer chassis of claim 2,wherein the two or more rail axles extend downwardly in the secondpositions to dispose the two or more road axles above a rail.
 4. Therailroad trailer chassis of claim 1, wherein the two or more rail axleseach include rail wheels, and the railroad trailer chassis is configuredto cause the rail wheels to contact a rail when the two or more railaxles are respectively in the second positions.
 5. The railroad trailerchassis of claim 1, wherein the two or more road axles are configured tobe moved between first and second positions.
 6. The railroad trailerchassis of claim 5, wherein the railroad trailer chassis is configuredto be driven or towed in the road mode when the two or more road axlesare respectively in the first positions.
 7. The railroad trailer chassisof claim 1, wherein the two or more road axles each include wheels andtires, and the railroad trailer chassis is configured to cause the tiresto contact a road when the two or more road axles are respectively inthe first positions.
 8. The railroad trailer chassis of claim 1, whereinthe work unit is removably attached to the railroad trailer chassis as amodular component.
 9. The railroad trailer chassis of claim 1, whereinthe railroad trailer chassis is configured to be controlled by anexternal remote control in a drone configuration.
 10. The railroadtrailer chassis of claim 1, wherein the railroad trailer chassis isconfigured to be driven in the road mode when the two or more rail axlesare respectively in the first positions.
 11. The railroad trailerchassis of claim 1, wherein the railroad trailer chassis is configuredto be towed in the rail mode when the two or more rail axles arerespectively in the second positions.
 12. The railroad trailer chassisof claim 1, further comprising one or more friction drives coupled tothe one of more of the road axles.
 13. The railroad trailer chassis ofclaim 12, wherein rail wheels of the rail axles are in friction contactwith road tires of the road axles, and the one or more friction drivesare configured to propel the railroad trailer chassis when the two ormore rail axles are respectively in the second positions.
 14. Therailroad trailer chassis of claim 12, wherein one or more of the railaxles are coupled to one or more of the rail axles.
 15. The railroadtrailer chassis of claim 1, wherein the two or more rail axles arerespectively configured to pivot between the first and second positions.16. The railroad trailer chassis of claim 1, wherein the two or morerail axles are coupled to the work unit.
 17. The railroad trailerchassis of claim 16, further comprising a lifting device configured tomove the two or more rail axles and the work unit between first andsecond positions together.
 18. The railroad trailer chassis of claim 17,further comprising a driving mechanism configured to propel the railroadtrailer chassis down a rail, the driving mechanism being coupled to thework unit such that the driving mechanism moves between first and secondpositions with the work unit.